Van der Wiel Attack
Caro-Kann Defense
1.e4 c6 2.d4 d5 3.e5 Bf5 4.Nc3 e6 5.g4
Also called the Shirov Attack. White aggressively expands on the kingside with 5.g4 to harass Black's bishop.
Fun fact: The Van der Wiel Attack was popular in the 1980s and was later a favorite of Alexei Shirov, which is why it is also called the Shirov Attack. Source
Practice this lineThe idea
White develops the queen's knight with 4.Nc3 and, after 4...e6, lunges with 5.g4 at the bishop on f5. Black's bishop usually retreats to g6, and White plans to chase it further with h4 and h5.
It is one of the sharpest ways to meet the Caro-Kann. White gives up long-term safety on the kingside for time and space.
Plans for White
After 5...Bg6, the main line continues 6.Nge2, heading for f4, and then h4 to threaten h5 against the bishop.
Keep the initiative: if Black gets time to break with ...c5 and develop, White's advanced pawns can become targets.
Plans for Black
Strike back in the center with ...c5 as soon as possible, and develop the king's knight to e7, where it can come to c6 or f5.
Watch the bishop on g6. Answer h4 with ...h5 or ...h6 at the right moment so it always has a square.
Watch out for
For Black, the bishop is the target. With pawns coming to h4 and h5 and a knight to f4, it can be trapped or won if it has no retreat. Before White's h5 arrives, make sure it has h7, or exchange it.
For White, the danger is the counterattack. If ...c5 opens the center while White's pawns are spread across the kingside, White's king has nowhere safe to go.